Fatigue tests of nodular cast iron at low and high frequency cyclic loading

Abstract Three melts of ferrite-pearlitic nodular cast iron with different charge composition were used for fatigue tests. Wöhler fatigue curves and fatigue strength were obtained, and microstructure and fracture surfaces were investigated. The aim of the paper is to determine the influence of charge composition on microstructure, mechanical and fatigue properties of synthetic nodular cast irons and their micromechanisms of failure. Fatigue tests were realised at low frequency sinusoidal cyclic push-pull loading (stress ratio R = −1) at ambient temperature (T = 20 ±5°C). They were carried out with using the fatigue experimental machine Zwick/Roell Amsler 150HFP 5100 at frequency f ≈ 120 Hz. The results of fatigue tests at low frequency cyclic loading are compared with fatigue properties at high frequency cyclic loading.

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Comparison of Fatigue Properties of Nodular Cast Iron at Low and High Frequency Cyclic Loading

Procedia Engineering ◽

10.1016/j.proeng.2017.02.263 ◽

2017 ◽

Vol 177 ◽

pp. 576-581 ◽

Cited By ~ 8

Author(s):

Alan Vaško ◽

Milan Vaško ◽

Juraj Belan ◽

Eva Tillová

Keyword(s):

Cast Iron ◽

Cyclic Loading ◽

High Frequency ◽

Nodular Cast Iron ◽

Fatigue Properties

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Study of the fatigue behaviour of synthetic nodular cast irons at low and high frequency cyclic loading

MATEC Web of Conferences ◽

10.1051/matecconf/201815707014 ◽

2018 ◽

Vol 157 ◽

pp. 07014 ◽

Cited By ~ 1

Author(s):

Alan Vaško ◽

Juraj Belan ◽

Eva Tillová

Keyword(s):

Cyclic Loading ◽

High Frequency ◽

Fatigue Testing ◽

Low Frequency ◽

Nodular Cast Iron ◽

Fatigue Behaviour ◽

Fatigue Tests ◽

Cast Irons ◽

Ultrasonic Fatigue ◽

The Relationship

The paper presents the results of low and high frequency fatigue tests carried out on nodular cast iron. The specimens of synthetic nodular cast irons from three different melts were studied in the high cycle fatigue region (from 105 to 108 cycles) using fatigue experimental equipments for low and high frequency cyclic loading. Low frequency fatigue tests were carried out at frequency f ≈ 120 Hz using the fatigue experimental machine Zwick/Roell Amsler 150HFP 5100. High frequency fatigue tests were carried out at frequency f ≈ 20 kHz using the ultrasonic fatigue testing device KAUP-ZU. Both of them were carried out at sinusoidal cyclic push-pull loading (stress ratio R = -1) at ambient temperature (T ≈ 20 °C). The relationship σa = f (N) and fatigue strengths were determined experimentally; mechanical properties, microstructures and fracture surfaces were investigated.

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Preliminary study for flaw detection in nodular cast iron by cyclic loading and thermography

NDT & E International ◽

10.1016/j.ndteint.2013.01.017 ◽

2013 ◽

Vol 56 ◽

pp. 28-37 ◽

Cited By ~ 4

Author(s):

Wolfgang Tillmann ◽

Xiaoqun Feng ◽

Gottfried Fischer ◽

Jens Nellesen

Keyword(s):

Cast Iron ◽

Cyclic Loading ◽

Flaw Detection ◽

Nodular Cast Iron ◽

Preliminary Study

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Influence of graphite morphology on static and cyclic strength of ferritic nodular cast iron

MATEC Web of Conferences ◽

10.1051/matecconf/201816514014 ◽

2018 ◽

Vol 165 ◽

pp. 14014 ◽

Cited By ~ 1

Author(s):

Christian Gebhardt ◽

Geng Chen ◽

Alexander Bezold ◽

Christoph Broeckmann

Keyword(s):

Cast Iron ◽

Nodular Cast Iron ◽

Tensile Tests ◽

Cyclic Strength ◽

Fatigue Tests ◽

Point Of View ◽

Experimental Point ◽

Suitable Material ◽

Material Parameters ◽

Perfectly Plastic

High silicon alloyed nodular cast iron consists of a purely ferritic matrix and graphite nodules, mainly. Varying wall thicknesses and manufacturing conditions result in different graphite morphologies throughout a structural component. From an experimental point of view, axial fatigue and tensile tests were carried out on specimens with differently degraded graphite. From a numerical point of view, the microstructure has been modelled using a finite element (FE) approach with representative volume elements (RVE). The RVE models were built according to micrographs of fatigue specimens. The generated RVEs determine effective material properties through elasto-plastic homogenization and were subsequently analysed using a shakedown approach. In shakedown theory, the material re-enters the elastic regime after a few cycles of initial plastic deformation. This work uses the shakedown theorem to derive a lower bound estimation of the endurance limit from a non-incremental simulation. Here, the material has to be modelled elastic-perfectly plastic. The major challenge in modelling nodular cast iron is to determine suitable material parameters for the graphite and ferrite phase, revealed by parameter studies on the static and cyclic model. By using reasonable material parameters, fundamental effects, observed in the fatigue tests, were reproduced on the model level.

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Fatigue Strength of Ductile Iron in Ultra-High Cycle Regime

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.874.43 ◽

2014 ◽

Vol 874 ◽

pp. 43-48 ◽

Cited By ~ 6

Author(s):

Robert Ulewicz ◽

František Nový ◽

Jacek Selejdak

Keyword(s):

Cast Iron ◽

Fatigue Strength ◽

Ductile Iron ◽

High Frequency ◽

Fatigue Testing ◽

Testing Machine ◽

Fatigue Tests ◽

Essential Factor ◽

Equipment Safety ◽

Sn Curve

Machine and equipment safety is the most essential factor that determines the choice of a particular material used in the construction phase. Failure analyses in engineering praxis demonstrate that nearly 90 % of all cases of failures are caused by fatigue. For popular technical applications such as cars and trains, the durability expected for some components ranges from 108to 1010loading cycles. However, only few studies have been carried out for more than 107cycles. The SN curve in the ultra-wide life region must be determined in order to ensure actual fatigue strength and safety of these components. This paper presents the results obtained from fatigue tests carried out by means of a high-frequency fatigue testing machine for the three grades of ductile iron: with ferritic-pearlitic matrix (GGG50), with pearlitic-ferritic matrix (GGG60) and ADI cast iron in the range from 106up to 1010cycles.

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Influence of Stress Mode on Failure Micromechanisms of Nodular Cast Iron

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.693.382 ◽

2014 ◽

Vol 693 ◽

pp. 382-387 ◽

Cited By ~ 2

Author(s):

Alan Vaško ◽

Milan Vaško

Keyword(s):

Cast Iron ◽

Nodular Cast Iron ◽

Mechanical Tests ◽

Fatigue Tests ◽

Bending Test ◽

Metallographic Analysis ◽

Cast Irons ◽

Fracture Surfaces ◽

Static Tensile ◽

Different Content

The paper deals with comparison of the failure micromechanisms of nodular cast iron at static, impact and fatigue stress. Several specimens of ferrite-pearlitic nodular cast irons with different content of ferrite in a matrix were used for metallographic analysis, mechanical tests and microfractographic analysis. Mechanical properties were found out by static tensile test, impact bending test and fatigue tests. The microfractographic analysis was made with use of scanning electron microscope on fracture surfaces of the specimens fractured by these mechanical tests. Fracture surfaces of analysed specimens are characteristic of mixed mode of fracture. Failure micromechanism of nodular cast irons is dependent on mode of stress.

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Fatigue of nodular cast iron at high frequency loading

Materialwissenschaft und Werkstofftechnik ◽

10.1002/mawe.201600519 ◽

2016 ◽

Vol 47 (5-6) ◽

pp. 436-443 ◽

Cited By ~ 3

Author(s):

A. Vaško ◽

L. Hurtalová ◽

M. Uhríčik ◽

E. Tillová

Keyword(s):

Cast Iron ◽

High Frequency ◽

Nodular Cast Iron

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Consideration of the transient material behavior under variable amplitude loading in the fatigue assessment of nodular cast iron using the strain-life approach

10.22541/au.160819674.49622055/v1 ◽

2020 ◽

Author(s):

Jan Hesseler ◽

Jörg Baumgartner ◽

Christoph Bleicher

Keyword(s):

Cast Iron ◽

Residual Stresses ◽

Fatigue Testing ◽

Cyclic Hardening ◽

Nodular Cast Iron ◽

Fatigue Tests ◽

Material Behavior ◽

Strong Impact ◽

Static Creep ◽

Cyclic Relaxation

The consideration of realistic load assumptions is important for the fatigue design of highly stressed nodular cast iron components for wind energy application. Especially in case of overloads causing elastic-plastic deformation, residual stresses may have a strong impact on fatigue life. In strain-controlled fatigue tests with constant and variable amplitudes, the influence of overloads on the lifetime was investigated. The overload was applied with the objective to create high tensile residual stresses. During fatigue testing the transient material behavior, cyclic hardening, cyclic relaxation of the residual stresses as well as quasi static creep effects, of the EN-GJS-400-18-LT was recorded and evaluated. To quantify the influence of the transient material behavior on the calculated lifetime, fatigue analyses are carried out with the strain-life approach, both with and without consideration of the transient material behavior. The results show that conservative damage sums are derived if the transient material behavior, especially the relaxation of tensile residual stresses, is neglected.

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